1. Technical Field
The present disclosure relates to transmitting data, and more particularly to devices and methods of transmitting data, source drivers using methods for transmitting data, and liquid crystal display (LCD) devices having devices for transmitting data.
2. Discussion of the Related Art
A liquid crystal display (LCD) device is a flat display device that uses liquid crystal to display images. Sizes of LCD devices are gradually increasing according to user demand. As the display sizes are increased, the numbers of pixels representing the images are increased and power consumption of the LCD devices is increased.
LCD devices generate electromagnetic noise as an unintended consequence of consuming power, and the electromagnetic noise is emitted as a form of electromagnetic radiation. The electromagnetic noise is often called electromagnetic interference (EMI).
FIG. 1 illustrates an environment for measuring electromagnetic interference (EMI) of an LCD device, and FIG. 2 is a graph illustrating international standards related to EMI.
As illustrated in FIG. 1, a method of measuring the EMI includes displaying H patterns on a panel of the LCD device and measuring the EMI level at a distance of about 3 or 10 meters from the LCD device using an antenna.
As illustrated in FIG. 2, the EMI level according to the CISPR 22 standard of the International Special Committee on Radio Interference is measured at a distance of about 3 meters from the LCD device. In a frequency bandwidth from 30 MHz to 238 MHz, the EMI level of the LCD device should not exceed 40 dB, and in a frequency bandwidth from 238 MHz to 1,000 MHz, the EMI level of the LCD device should not exceed 49.8 dB.
Also, as illustrated in FIG. 2, the EMI level according to the CISPR 22-B standard is measured at a distance of about 10 meters from the LCD device. In a frequency bandwidth from 30 MHz to 238 MHz, the EMI level of the LCD device should not exceed 30 dB, and in a frequency bandwidth from 238 MHz to 1,000 MHz, the EMI level of the LCD device should not exceed 37 dB.
The EMI level of the LCD device is important because the LCD device is considered to be defective if the EMI level of the LCD device does not satisfy the CISPR 22 and CISPR 22-B standards.
Generally, EMI is represented as an electric field intensity E that is calculated by Equation 1.
                              E          =                                    kIlf              r                        ⁢                          (                              uVm                                  -                  1                                            )                                      ,                            [                  Equation          ⁢                                          ⁢          1                ]            
where k indicates a constant, I indicates a current, l indicates a conducting wire length, f indicates a frequency and r indicates a distance.
Referring to Equation 1, the electric field intensity E is proportional to the current I, the conducting wire length l and the frequency f, and is inversely proportional to the distance r. The LCD device has a relatively high power consumption since a large amount of data is transmitted, line by line, over a relatively short time period. Therefore, a method of reducing the EMI level includes reducing the current I and the conducting wire length l.